“Like your namesake (NGC 3314), Bill?”

Now you’re playing on a mania. Not just that one pair – Galaxy Zoo has delivered another 2000 or so useful for study of the foreground dust, and that’s before they turned their energies to Hubble Zoo. I promise not to write a paper on each one.

“…(Which reminds me of a very amusing narrowband plate of NGC 404 I took years ago, a trail of sausages from Beta Andromedae crossing the field).”

I had a similar experience photographing NGC 404 with a broadband IIa-O plate many years ago and that emulsion’s blue sensitivity didn’t help the situation wrt Beta Andromedae. If only GALEX imagery was available at the time (making NGC 404 an easy, intriguing target): http://www.galex.caltech.edu/media/glx2008-02r_img01.html

“Now, if you have one galaxy photobombing another, then you’ve got something…”

Like your namesake (NGC 3314), Bill?

http://en.wikipedia.org/wiki/Person_from_Porlock

But then for those studying the edge-on spiral in the lower left-hand corner enmeshed within PGC 39058 then that dwarf galaxy is being the “Person from Porlock” .. But then again for those studying *another* galaxy hidden behind *that* edge on spiral in the lower left hand corner that edge on spiral emmeshed within PGC 39058 is the “Person from Porlock” and.. so on, ad infinitum.

PS. I wonder if people studying the *star* find it annoying that the light from that dwarf galaxy keeps getting in the way and confusing things?

—-

“Big fleas have little fleas,
Upon their backs to bite ‘em,
And little fleas have lesser fleas,
and so, ad infinitum.”

http://en.wikipedia.org/wiki/The_Siphonaptera

Just a thought – but parts of that sequence are recoloured footage of the same sequences Kubrick used in Dr Strangelove, as the B52 was heading towards its doom…

‘Scuse me while I contemplate how to get a pun out of “Dr Strangelove, or How I Learned to Stop Worrying and Love the Photobomb”…

The star is in reality a red giant about 650 light years away. It shines with about 200 times the luminosity of the Sun, so it appears to me that we’re looking at a star much like the Sun but far older.

Would that luminosity figure be bolometric (incl. all wavelengths) or just visual?

Is HD 106381, like so many red giants, a variable?

Interesting to reflect that the view of that galaxy would be almost the same as seen from HD 106381 – except for not having HD 106381 in the way at night!

I wonder too if our own Sun is in the way of anything as seen from alien skies?

@ 14. Navneeth Says: Phil, why is this post tagged Antiscience?

Perhaps because the star is being anti-the scientists trying to observe the galaxy?

I guess you could call HD 106381 an obstacle to science – although it also offers a scientific target of its own right when it comes to studying red giant stars.

@ 6. MT-LA :

We call it being a bonehead here in Oz.

@ 9 & 23. Regner Trampedach Says:

Oh, man! – not a single laugh at my joke @ 9? I didn’t think it was that lame. Cheers, Regner

Well you raised a smile from me with that. I liked it.

And let’s not forget dwarf galaxy Leo I

Which is a mere 12 arc minutes away from the 22nd brightest star in the whole sky, Regulus.

There’s a good Astronomy Picture of the day shot of that here :

http://antwrp.gsfc.nasa.gov/apod/ap060619.html

Regulus is also the closest B type star to our Sun at a distance of 77 light years and rotates so quickly that it is shaped, as Ken Croswell writes, like a pumpkin – albeit one composed of blue-hot plasma :

http://kencroswell.com/RegulusIsOblate.html

Linked from that article you can also find another of Ken Croswell’s articles – ‘Stellar Theft Sends Guilty Star Into a Spin’, July 12, 2008, New Scientist page 16 – explaining that the Regulan rapid rotation is probably due to an as-yet unconfirmed (?) white dwarf component of a system already containing more distant orange & red dwarf companions.

Proper motion will carry it away very gradually taking it out of the field of vision there.

Of course, the proper motion of *other* stars may then bring them into that field of view replacing it!

This process will take time natch depending on how close or distant the star is and its exact motion.

I wonder if anybody’s got images of galaxies with foreground stars compared over decades or longer showing this effect and enabling us to get a more detailed less obscured view of galaxies affected by blocking foreground stars?

It isn’t all that obscured by Regulus. I found it very easy to image compared to NGC 404. My post on it at the Baut forum is at:
http://www.bautforum.com/showthread.php/72431-Leo-I

Other than keeping Regulus out of the image nothing was needed to avoid its influence. A light leak letting in light of two LED’s were far more of a problem.

Rick

Careful, or the nutters will descend in droves, boo-hooing because you’re making fun of ‘em.

That being said, Ha.

Send up the space shuttle again.

“the light from an object fades with the square of its distance”

You might want to look up the Inverse-square Law. It basically just means that if energy is radiating away from a point source then it has to spread out as it gets further away. Since it acts like a sphere expanding from the center it must get less and less “dense” the further it gets from the center.

The surface area of a sphere is 4πr², or “four times pi times the radius of a circle squared”.

The photo doesn’t have a scale, but I would estimate that the star and the center of the galaxy are about 30 arcseconds apart, or 1/120 of a degree. The 10,000 stars in the sky are, on average, about two degrees apart. Shoot a galaxy into this matrix, and it should ‘land’, on average, within a degree or so of a star. The probability of a random galaxy shot into the matrix being closer than d degrees to a star would go as d**2 (d squared). Shoot 10,000 galaxies into this matrix and one of them should then land within about 1/100 of a degree of a star. So, having one encounter this close seems within the normal bounds of expectation.

Can one of you egg head brainbox boffins explain that in idiot please. Have not heard that before but it sounds useful to know.